On a bright sunny morning on September 11, 2001, hijackers took control of four U.S. commercial airplanes. The terrorists crashed two planes into two World Trade Center Towers in New York City. Forty minutes later, hijackers crashed another plane into the Pentagon in Washington, D.C. Passengers on a fourth hijacked plane resisted, and the plane crashed in an empty Pennsylvania field. The tragic events of September 11 killed nearly 3,000 people, scarred Americans, and changed the world forever.